title: Role of p53 serine 46 in p53 target gene regulation.
abstract: The tumor suppressor p53 plays a crucial role in cellular growth control inducing a plethora of different response pathways. The molecular mechanisms that discriminate between the distinct p53-responses have remained largely elusive. Here, we have analyzed the p53-regulated pathways induced by Actinomycin D and Etoposide treatment resulting in more growth arrested versus apoptotic cells respectively. We found that the genome-wide p53 DNA-binding patterns are almost identical upon both treatments notwithstanding transcriptional differences that we observed in global transcriptome analysis. To assess the role of post-translational modifications in target gene choice and activation we investigated the genome-wide level of phosphorylation of Serine 46 of p53 bound to DNA (p53-pS46) and of Serine 15 (p53-pS15). Interestingly, the extent of S46 phosphorylation of p53 bound to DNA is considerably higher in cells directed towards apoptosis while the degree of phosphorylation at S15 remains highly similar. Moreover, our data suggest that following different chemotherapeutical treatments, the amount of chromatin-associated p53 phosphorylated at S46 but not at pS15 is higher on certain apoptosis related target genes. Our data provide evidence that cell fate decisions are not made primarily on the level of general p53 DNA-binding and that post-translationally modified p53 can have distinct DNA-binding characteristics.
authors.affiliation: Department of Molecular Biology, Faculty of Science, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands.
authors.forename: Leonie
authors.initials: L
authors.lastname: Smeenk
authors.forename: Simon J
authors.initials: SJ
authors.lastname: van Heeringen
authors.forename: Max
authors.initials: M
authors.lastname: Koeppel
authors.forename: Bianca
authors.initials: B
authors.lastname: Gilbert
authors.forename: Eva
authors.initials: E
authors.lastname: Janssen-Megens
authors.forename: Hendrik G
authors.initials: HG
authors.lastname: Stunnenberg
authors.forename: Marion
authors.initials: M
authors.lastname: Lohrum
mesh_terms: D001665:Binding Sites; D045744:Cell Line, Tumor; D002843:Chromatin / Q000378:metabolism; D047369:Chromatin Immunoprecipitation; D016000:Cluster Analysis; D004247:DNA / Q000378:metabolism; D003609:Dactinomycin / Q000494:pharmacology; D005047:Etoposide / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D015894:Genome, Human / Q000235:genetics; D006801:Humans; D058977:Molecular Sequence Annotation; D010766:Phosphorylation / Q000187:drug effects; D010768:Phosphoserine / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D020539:Sequence Analysis, Protein; D012694:Serine / Q000378:metabolism*; D013329:Structure-Activity Relationship; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D002843:Chromatin; D016159:Tumor Suppressor Protein p53; D010768:Phosphoserine; D003609:Dactinomycin; D012694:Serine; D005047:Etoposide; D004247:DNA